Dummy Pattern Fills Stepwise Portions for Uniform Deposition
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Solution Overview
Problem
Increased integration density in semiconductor devices leads to challenges such as difficulties in layer deposition, reduced uniformity in etching processes, and deterioration in device reliability due to decreasing line widths and increasing aspect ratios.
Innovation Solution
A method of fabricating semiconductor devices involves forming dummy patterns on stepwise portions of substrates to reduce height differences, allowing for a uniform material layer coverage and polishing process, which reduces the number of stepwise portions and improves thickness uniformity, thereby enhancing the reliability and integration of semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If integration density of semiconductor devices is increased, then device functionality and capacity are improved, but manufacturing difficulty and process uniformity deteriorate due to decreasing line width and increasing aspect ratio
Solution Approach 1:
A filler pattern is formed in advance in the non-cell region before the main deposition process. This preliminary structure fills the stepwise portion created by the substrate structure, enabling subsequent material layers to be deposited uniformly across the entire surface without the complications of high aspect ratio features.
Solution Approach 2:
The filler pattern is specifically placed only in the non-cell region where stepwise portions exist, leaving the cell region patterns unchanged. This localized approach addresses the manufacturing difficulty only where needed while preserving the functional integrity of the active device regions.
2Quantity of substance
If line width and space are decreased to achieve higher integration, then device capacity increases, but etching uniformity and reliability deteriorate
Solution Approach 1:
The filler pattern is formed beforehand to create a uniform surface topology. This preliminary structure ensures that when etching processes are applied to subsequent layers, the material can be removed uniformly across the entire surface, including both cell and non-cell regions, eliminating the stepwise effects that would cause non-uniform etching.
Solution Approach 2:
The filler pattern creates an equipotential surface by filling the stepwise portions to the same height as the surrounding patterns. This eliminates height differences that would cause non-uniform etching, ensuring that all areas experience the same etching conditions and achieve consistent results.
3Quantity of substance
If aspect ratio of patterns is increased to achieve higher integration, then device capacity increases, but process uniformity and reliability deteriorate
Solution Approach 1:
The filler pattern is formed in advance to compensate for the high aspect ratio structures in the non-cell region. By filling these stepwise portions before subsequent processing, the patent eliminates the reliability issues that would arise from processing high aspect ratio features, such as poor material coverage and non-uniform etching.
Solution Approach 2:
The patent converts the harmful effect of stepwise portions (which cause poor deposition and etching uniformity) into a benefit by filling them with a filler pattern. This transforms the problematic high aspect ratio regions into uniform surfaces that can be processed reliably, while the filler material itself becomes part of the final device structure.
Data Source
AI summary
A method of fabricating a semiconductor device includes providing a substrate including a pair of first regions and a second region therebetween, forming first patterns on the respective first regions to at least partially define a stepwise portion at the second region, and forming a dummy pattern that at least partially fills the stepwise portion. The dummy pattern may be an electrically floating structure. The dummy pattern may be formed as part of forming second patterns on the respective first regions, and the dummy pattern and the second patterns may include substantially common materials. Because the dummy pattern at least partially fills the stepwise portion at the second region, the material layer covering the second patterns and the dummy pattern may omit a corresponding stepwise portion.